I've never met him or anything, but my good friend (who is deaf) did and he knows sign language (most likely from dating Marlee Matlin who is also deaf) and he talked (signed) with her for like half an hour. She said it was really cool. And this was sometime after he had broken up with Matlin, so that's neat that he still retained his sign language skills.

This got me thinking about the episode Silent World and wondering if RDA was dating Marlee Matlin during the time of that episode because he shows some instinct towards sign language in that episode.